Practical Guide to Lightcurve Photometry and Analysis (eBook)

Brian Warner has been an astronomer for 40 years. He ran the Minor Planet Observer for ten years, and has contributed more than 60 papers to the Minor Planet Bulletin, along with regular articles. He lives in Colorado, USA.

Foreword 5
Preface 7
Contents 9
Getting Started 14
1.1 What Is Lightcurve Photometry? 16
1.2 What Lies Ahead 17
Targets of Opportunity 19
2.1 Asteroids 19
2.2 Variable Stars 24
2.3 Eclipsing Binary Lightcurve Characteristics 27
2.4 Cataclysmic Variables 29
2.5 Cepheids 30
2.6 Long Period (Mira) Variables 30
2.7 Semi-Regular Variables 30
2.8 Other Targets 31
2.9 Summary 32
Photometry Fundamentals 33
3.1 A Little Bit of History 33
3.2 The First Color-Based Systems 34
3.3 The Johnson–Cousins Standard 35
3.4 Setting the Standard 36
3.5 Seeing Red 36
3.6 CCDs and Standard Magnitudes 36
3.7 Landolt Standards 37
3.8 Henden Sequences 38
The Photometry Primer 39
4.1 Instrumental Versus Standard Magnitudes 39
4.2 Air Mass 40
4.3 Extinction 41
4.4 Transforms and Nightly Zero-Points 43
4.5 Differential Versus All-Sky Photometry 44
4.6 Seeing and Scintillation 47
4.7 Matching Pixel Size to Seeing 48
4.8 Bias Frames 48
4.9 Dark Frames 49
4.10 Flat Fields 49
4.11 Photometry Apertures and Annuluses 53
4.12 Reporting Errors 58
Photometric Reductions 59
5.1 The Different Path 60
5.2 The Differential Formula 61
5.3 Clear to Visual Conversions 62
5.4 First-Order Extinctions – Are They Really Necessary? 62
5.5 The Same Color Index 64
5.6 Transforms First 65
5.7 Finding Transforms 65
5.8 The Hidden Transforms 68
5.9 First-Order Extinction 69
5.10 Finding First-Order Extinction (Modified Hardie) 71
5.11 A Variation on the Modified Hardie method 73
5.12 Finding First-Order Extinction (Comp Star) 74
5.13 Comparison and Target Standard Color Index Values 75
5.14 Find the Color Indices of the Comparisons and Target 76
5.15 The Comparison Star Standard Magnitudes 78
5.16 Finding the Comparison Star Standard Magnitudes 79
5.17 Target Standard Magnitudes 80
5.18 Finding the Standard Magnitudes of the Target 80
5.19 The Different Path’s End 83
5.20 A Minimalist Approach 83
5.21 Using the Minimalist Approach for Standard Magnitudes 84
Second Order Extinction 89
6.1 Deriving a Single-Color Approach 89
6.2 The Slope of Slopes Method 90
6.3 When Is the Second-Order Term Applied? 92
6.4 Summary 93
Telescopes and Cameras 94
7.1 The Telescope 94
7.2 The CCD Camera 98
7.3 Digital and Web Cameras 106
7.4 Filter Wheels 107
7.5 Guiding Considerations 108
Imaging and Photometry Software 109
8.1 Image Acquisition Software 109
8.2 Specific Features 110
8.3 Photometry Software 112
8.4 Conforming to Accepted Standards 116
8.5 Manual Versus Automated Measuring 119
Collecting Photons 121
9.1 The First Step – Getting the Right Time 121
9.2 Planning the Observing Program 122
9.3 Selecting Targets 123
9.4 General Considerations 124
9.5 Asteroids 125
9.6 Variable Stars 127
9.7 The Observing Run 128
9.8 Measuring Images 130
9.9 From Image to Data 133
9.10 The Hands-On Approach for Measuring Images 135
9.11 Checking the Comparison Stars 139
9.12 The Automated Approach to Measuring Images 140
Analyzing the Data 143
10.1 The Quality of Data 143
Period Analysis 147
11.1 About Merging Data and Setting Zero-Points 147
11.2 A Simple Start 149
11.3 To What Precision 152
11.4 Refining the Search Process 153
11.5 The Amplitude of the Lightcurve 154
11.6 Aliases in Depth 155
11.7 Plotting the Half-Period 159
11.8 A Specific Alias Example 160
11.9 The Case of 3155 Lee 161
11.10 Period Analysis on a Spreadsheet 162
11.11 From Lightcurve to Shape 167
Building Star Systems 171
12.1 Getting Started 171
12.2 Binary Maker 174
12.3 The Many Possibilities 176
12.4 The Effects of Changing the Inclination 176
12.5 The Effects of Temperature Changes in the Primary 178
12.6 The Effects of Temperature Changes in the Secondary 179
12.7 The Effects of Changing the Mass Ratio 181
12.8 The Effects of Gravity/Limb Darkening and Reflection 182
Publishing Your Data and Results 183
13.1 Confirm Before You Publish 183
13.2 Asteroids 185
13.3 Variable Stars 186
13.4 Learn by Association 187
Bibliography 190
Asteroids 190
Variable Stars 191
CCD Imaging 191
Image Processing 192
Photometry 192
Telescope Control Software 192
Camera Control Software 193
Photometry Software 193
Miscellaneous 193
Organization Web Sites 194
Glossary 195
Appendix A: Constellation Names 211
Appendix B: Transforms Example 213
Example Transforms Data 213
The Spreadsheet 214
The Hidden Transforms 216
Appendix C: First-Order (Hardie) Example 218
The Data 218
The Spreadsheet 220
Appendix D: First-Order (Comp) Example 223
The Data 223
The Spreadsheet 223
Appendix E: Standard Color Indices 225
The Data 225
The Spreadsheet 225
Appendix F: Comparison Standard Magnitudes 228
The Data 228
The Spreadsheet 229
Appendix G: Target Standard Magnitudes 231
The Data 231
The Spreadsheet 232
Appendix H: Landolt/ Graham Standard Fields 234
Graham Fields 234
Appendix I: Henden Charts 256
Close but not Quite 257
Appendix J: Hipparcos Blue–Red Pairs 288
Steps used to produce the List 288
Hipparcos Blue–Red Pairs 290
Appendix K: SDSS Blue–Red Pairs 294
Index 298